Telecommunications networks permit the reliable, rapid, and secure exchange of information for individuals and businesses on local, regional, and global scales. Such networks are fundamental to the operation of all electronic commerce (e-commerce) and mobile commerce (m-commerce) systems, which are revolutionizing the business methods of companies across the world. Because of the desirability of the services provided by the networks, they are popular targets for criminals who attempt to defraud the network operators by stealing the services they provide and selling them on to third parties at a substantial discount. For example, it is known that criminals steal network time that is assigned to a calling tariff, and then sell this stolen time on to third parties. The same problem is encountered with pre-paid call time. The criminals are aided in this enterprise by the anonymity of telecommunications networks and the insecurity of their physical infrastructure. It is also relatively easy to gain access to hardware from which fraudulent attacks can be launched.
Fraud is not only a serious problem for the operators of telecommunications networks, but also for the providers of services that make use of them. In addition to the criminal acts of selling stolen services to third parties, the fraudulent use of credit and other payment cards for purchasing goods and services over telecommunications networks is a persistent occurrence. One of the primary problems with such fraudulent acts is the cost implications of providing services that ultimately are not paid for. To combat fraud, sophisticated fraud detection systems are used to monitor the activity on a network for suspicious behavior that may indicate that a fraud is in progress. Some systems operate by comparing a voice sample of a user of a telephone number with a pre-stored voice print of a legitimate user. If the voice sample does not match the voice print, it is taken as an indication of a fraudulent transaction. However, systems such as this are relatively complex and, as a result, their reliability tends to be rather low. As a consequence, there is a need for a system's operator to employ large fraud investigation teams to analyse each possible fraud in greater detail so as to determine whether a fraud has actually been identified, and, if so, to authorize the suspension of the service that is being exploited.
It is an object of the present invention to provide a system and method of reduced complexity for detecting fraudulent transactions, and which reduces the human contribution requirement to the fraud detection process. It is a further object of the invention to provide a method and system for detecting fraudulent transactions of improved reliability.